1. Field of the Invention
The present invention is related to body fluid aspiration devices and techniques and, more particularly, is directed towards a body fluid aspiration device and technique which substantially reduces the risk of complications resulting from accidental puncture of the internal organs in the vicinity of the body fluid to be aspirated.
2. Description of the Prior Art
There are many common medical procedures which require fluids to be withdrawn from the body.
Fluid accumulation occurs abnormally in many pathologic situations and its removal may be accomplished as part of a diagnostic evaluation or as a form of therapy. The most common examples of the former are fluid forming around the lung, intestines and heart. The most common reasons for a therapeutic fluid removal would be as a result of pressure build-up of fluid around certain organs which would cause specific organ dysfunction syndromes. It is possible, in fact, to accumulate several liters of fluid in such areas.
A thoracentesis is the procedure for removal of fluid around the lungs. Other procedures are known, such as a paracentesis (withdraw of fluid from the abdomen), or a pericardiocentesis (withdrawl of fluid around the heart).
In a thoracentesis procedure, for example, a hollow needle is inserted through the chest wall. A syringe is connected to the end of the needle, usually via a three-way stop-cock valve. When the fluid mass is located, the fluid is aspirated into the syringe with the valve in a first position. Once the syringe is filled, the valve is switched and fluid is ejected from the syringe into a stand-by receptacle. This procedure is repeated until all of the fluid has been withdrawn, whereafter the needle is removed from the cavity.
The thoracentesis procedure is unfortunately accompanied by a significant risk of a complication known as pneumothorax. A pneumothorax is a collapsed lung which results from lung puncture and associated leakage of air into the pleural space with equalization of atmospheric and intrapleural pressure. Intrapulmonary hemorrhage may also result from accidental puncture of intrapulmonary blood vessels. In a thoracentesis there is also a smaller, but equally undesirable, risk of visceral (liver and spleen) puncture with subsequent intraorgan bleeding and death.
In a thoracentesis, the actual time of the lung or visceral puncture is unknown, although there are three distinct possibilities. The puncture could occur at the time of entry of the needle into the chest; however, this is unlikely if fluid is present since there is a reasonable distance to the lung parenchyma. A second possibility is that the puncture could occur while fluid is being aspirated from within the pleural space; this is more likely since it is frequently difficult to stabilize the needle and prevent to and fro movement which may accidentally push the needle into the visceral organ. Finally, the puncture could occur at the end of the procedure; this is highly likely since, at that time, there is only a small amount of fluid remaining and the lung parenchyma is closest to the tip of the needle.
The same types of risks occur, with respect to other internal organs, during a paracentesis, pericardiocentesis, and other body fluid aspiration procedures.
U.S. Pat. No. 3,982,546 evidences an improved body fluid draining device wherein, after the hollow needle is inserted into the body cavity to be drained, a flexible plastic cannula is positioned through the needle into the cavity whereafter the outer needle is withdrawn. The plastic cannula is connected to a syringe or other fluid withdrawal device. While providing an improvement over prior techniques, use of this device nevertheless has several drawbacks. For example, an inexperienced operator may accidentally attempt to withdraw the plastic cannula before the needle is withdrawn. Due to the fact that the plastic cannula when fully inserted extends appreciably beyond the tip of the needle, premature withdrawal of same can sever the cannula within the cavity which can, in turn, require surgery to remove the severed portion. Additionally, the tip of the plastic cannula, while not as sharp as the needle point, is nevertheless sufficiently hard to damage the lung or other organs if improperly used.
U.S. Pat. No. 3,777,757 to Gray et al teach a sucking wound plug and chest aspirator which includes a catheter for placement through a chest wound and includes an inflatable bag which, upon inflation, is intended to fit snugly within the edges of the chest wall which define the perforation. The terminal distal end of the catheter is provided with a cushioning means for preventing damage to any delicate internal organs.
I am aware of many different types of balloon catheters utilized in various medical procedures. For example, a Fogarty catheter employs a balloon to extricate clots from the vascular beds. Another familiar use of a balloon catheter is as a retention device for retaining a tube in, for example, the bladder. Endotracheal devices frequently use a balloon to surround a rather rigid plastic tube to prevent necrosis of the airway. A Swan-Ganz catheter is also known and is used in cardiac catherization. It has a balloon around a plastic catheter to protect the heart muscle from being irritated by the plastic catheter and to facilitate movement of the catheter into a predetermined location to obtain pressure measurements.
Prior art United States patents of which I am aware which exemplify the above-referenced state of the art include U.S. Pat. Nos. 3,799,173; 3,954,110; 3,438,375; 1,922,084; 3,703,899; 3,833,003; 3,952,742; 3,448,739; 3,634,924; and 3,746,003.